Fluid heat exchange apparatus



Dec. 24, 1940. c s sMjTH 2,226,445

" FLUID HEAT EXCHANGE APPARATUS Filed May 5; 1937 3 Sheets-Sheet 1 56 VF1 Z 58 Y L 5/- v /.'T\\ 28 20 1g n fl INVENTOR. Char/e5 CSTSITIfLh C.S. SMITH FLUID HEAT EXCHANGE APPARATUS 7 Dec. 24-, 1940.

s She ets-Sheet 2 Filed May 5, 1957 p INVENTIOR Char/es SSmiih ORNEY.

De. 24, 1940. c. 5. SMITH FLUID HEAT EXCHANGE APPARATUS Filed May 5,1937 3"Sh eets -Sheet s INVENTORJ Char/es S $771M ORNEY.

Patented Dec. 24, 1940 UNITED STATES FLUID HEAT EXCHANGE APPARATUSCharles S. Smith, Westfield, N. J assignor to The Babcock & WilcoxCompany, Newark, N. J., a corporation of New Jersey I Application May 5,1937, Serial No. 140,812

3 Claims.

This invention relates to steam boilers and it is particularly concernedwith a steam boiler associated with a superheater in such a manner thatthefinal temperature of the superheated 5 steam may be maintained at asubstantially uniform value over a wide range of boiler capacities.

It is an object of the invention to provide a boiler in the operation ofwhich gas mass flow over the superheater may be regulated so as to 10maintain a desired superheat even though boiler capacity and gas flowvaries over a wide. range.

Another object of the invention is to provide a boiler having uprightsteam generating tubes subjected to horizontal gas flow and associated15 with a superheater in the manner above indicated.

It is also an object of the invention to provide an effective control ofthe flow of heating gases over a superheater associated with a boiler of20 the type having vertically extending tubes connected to and arrangedlongitudinally of a lower drum and one or more upper drums, andcharacterized by a generally horizontal multiple pass gas flow over thetubes.

Other objects of the invention will appear as the accompanying.description proceeds.

The invention will be described with reference to certain embodimentsthereof which are shown in the accompanying drawings.

In the drawings:

Fig. 1 is a horizontal section of an illustrative embodiment indicatingthe relationship of the furnace to the steam generating tubes and thesuperheater. This view is taken on the line ll of Fig. 2.

Fig. 2 is a view in the nature of a vertical section taken on the line22 of Fig. 1 and looking in the direction of the arrows.

Fig. 3 is a view in the nature of a vertical section of the damperoperating mechanism indicated in Fig. 2 of the drawings.

Fig. 4 is a detailed view in horizontal section showing a part of thedamper and operating 45 mechanism on an enlarged scale.

Fig. 5 is a view in the nature of a perspective View showing a part ofthe operating mechanism by which the dampers for the superheater bypassare controlled.

59 Fig. 6 is a detailed View, substantially in horizontal section,showing the relation ofthe damper 52 to the tubes 62, and the manner inwhich the damper is supported by the tubes.

Fig. 7 is an elevation of the structure indi- 55 cated in Fig. 6 of thedrawings.

Fig. 8 is partly a vertical sectional View on the line B8 of Fig. '7. I

The boiler indicatedin Fig. 2 of the drawings includes a steam andwaterdrum l connected to a submerged drum I2 by upright steam generatingtubes l4. The furnace [6 associated with this boiler is defined by walltubes l8 and floor tubes 20. The latter are connected to the drum [2 soas to supply water to the tubes l8 through the header 22. The tubes l8have their upper por- 10 tions bent to define the room 24, and at theupper end of the roof they are connected with the drum l0.

The furnace wall tubes l8 may be covered as indicated in Fig. 1, withceramic refractory ma terial 25, and the floor tubes are covered withsmooth face metallic blocks 28. At the end of the furnace an ash pit 30is located.

Referring to Fig. 1 of the drawing's, the par- 7 tition or baffle 32, ofceramic refractory mate rial, is supported by the'front row of tubes 34,and closes the spaces between them for a part of the distance across theboiler setting. Between'the end of this baflie and the boiler wall 36the furnace gases have their outlet from the furnace. The gases flowthrough this outlet and through two parallel gas passes 40 and 42leading to the second and third convection passes of the boiler. Thesegas passes are defined by the outside setting wall 36 and the transversebaiiles 43 and 44 extending from front to rear between uprighttubularelements forming heating surfaces of the installation. As shownin Fig. 1, the gas pass 42 is a superheater bypass in which the steamgenerating tubes 46 are positioned. Inthe other of the parallel passesthere is a superheater 48 having upright tubular elements extendingacross the path of the furnace gases. The superheater is screened byrows of steam generating tubes 50 interposed between the furnace and thesuperheater.

The draft loss through the bypass 42 due to the restriction of the steamgenerating tubes 46 is less than the draft loss due to the restrictionin the main pass 40 resulting from the closely spaced superheater tubes48. Opening the dampers 5258 will accordingly divert flow of gases fromthe pass 40 to pass 42.

In order that superheat may be adequately controlled and a substantiallyuniform superheat maintained over a wide range of furnace gas flow, theflow of furnace gases is proportioned between the parallel gas passes 40and 42. This is accomplished in the illustrative embodiment by dampers52, 54, 56, and 58. The ar- 55 rangement of these dampers with referenceto the steam generating tubes, and the mechanism for operating thedampers, is clearly indicated in Figs. 3, 4, and 5 of the drawings. Fig.3 indicates the dampers as pivoted upon horizontal rods held in positionby lugs 60 preferably welded to the rear tubes 62 of the bank of steamgenerating tubes. These dampers are moved from their positions indicatedin full lines in Fig. 3 of the drawings to their dotted-line positionsby operating mechanism including a link 64 and connecting rods 66 and 68pivotally associated with the link at I0 and I2. The connecting rodsextend through openings I4 and I6 formed in the rear boiler wall I8 andat their outer ends they are connected to bell-cranks and 82 pivotallymounted on brackets 84 and 88 for corresponding movements. Thesebrackets are fixed to the wall 18 so .as to maintain the bell-cranks intheir operative positions.

The bell-cranks 80 and 82 are connected by a rod 88 and are moved totheir adjusted positions by the operation of a handwheel 90 fixed uponan upright shaft 92 which carries a worm 94 at its upper end. This wormis fixed upon the shaft 92 b etween the arms 96 and 98 of a bracket I00through which the bell-crank trunnion I02 rotatably extends. Asindicated in Fig. 5 of the drawings, the worm 94 meshes with a worm gearsector I04 which is fixed upon the trunnion I02. The .latter isrotatable in bearings formed in arms of the bracket 86, and betweenthese arms the bell-crank 82 is fixed to the trunnion I02. Thus,operation of the handwheel causes corresponding pivotal movements of thebell-cranks 80 and 82 and consequently moves the dampers 52-58 todesired positions. Various positions of the dampers are designated by anindicator IIO movable by the turning of the shaft 92 with respect toindicia which form a scale on the bracket H2. The pointer H0 ispreferably carried by a sleeve II4 on the shaft 92.

Theopenings I4 and I6 are closed by movable seal plates I20 and I22which are movable vertically with the connecting rods 66 and 88. As

indicated in Figs. 3, 4, and 5 of the drawings, the connecting rodsextend through openings in theseplates, and the seal plates are slidablein guideways formed beneath parallel plates I26 and I28 fixed withreference to the boiler wall I8. The connecting rods'66 and 68 arefreely slidable through the plates I20 so that the dampers may be movedto any desired position, and the plates I28 are always maintained in gassealing relationship to the boiler wall.

The shaft 92 may also be automatically operated by devices which areresponsive to changes in steam flow, or in response to changes insuperheat from a desired value, or by other appropriate variables. Withthe use of such devices, the superheat may be maintained at a desiredvalue, and compensatory adjustments are effected for the usualvariations in gas flow which would otherwise make the superheatirregular.

As indicated particularly in Fig. 2 of the drawings the dampered outletof the superheater bypass42 extends over only a part of the verticalextent of the bypass. Below the outlet, the bypass is closed off by abaille I30 which may be formed by refractory blocks held in positionbetween two rows of the boiler tubes. A similar baffle extends from thetop damper 52 to the drum I0.

From the outlets of the parallel gas passes 40 and 42 the furnace gasesfiow through a gas pass I34 defined by the baflle 44 and a parallelbafile I38. A furnace gas space I38 between the small diameter steamgenerating tubes I40 and the tubes 32 facilitates the turning of thegases from the gas pass I34 to the last gas pass I42. From the latter,the furnace gases may pass to an air heater, or directly to a stack orsuitable draft inducing equipment.

The specific construction of the dampers indicated in Fig. 3 of thedrawings may be such as that indicated in Figs. 6, 7, and 8. Here, eachindividual damper consists of an alloy shell 320, the metal of which hashigh heat resisting properties. This shell, for insulating purposes, andfor lightness of construction, is filled with a non-combustible heatinsulating material 322, and the shell is thereafter sealed in anappropriate manner, such as by welding. The shell has upper and lowerlugs 324 and 326, the former of which receive the rod 328 upon which thedamper is pivoted. This rod is supported in operative position by thebrackets 330 and 332 which are welded to the tubes 62 in the positionsshown. The lower lugs 326 are provided with openings to receive the pinsby which the link 64 is pivotally related thereto.

I claim:

1. A steam boiler having an upper steam and water drum, a lower waterdrum, a vertically disposed convection heated bank of steam generatingtubes extending between and connected to'said drums along the lengththereof, means forming a furnace chamber laterally of the spacecontaining said tube bank and communicating therewith at only one end,bame means extending transversely of said tube space and arranged todivide said tube space into a plurality of serially connected gas passesextending transversely of said tube bank, means for effecting asubstantially horizontal flow of heating gases through said seriallyconnected gas passes, an intermediate baffle dividing the first of saidserially connected gas passes into two parallel gas passes, asuperheater having its tubes disposed in one of said parallel gas passeswhile some of the steam generating tubes are disposed in the other, anda gas flow regulator disposed adjacent the outlet of one of the parallelpasses to selectively control the proportioning of the furnace gas flowbetween the parallel passes and thereby control superheat.

2. A steam boiler having an upper steam and water drum, a lower waterdrum, a vertically disposed convection heated bank of steam generatingtubes extending between and connected to said drums along the lengththereof, means form ing a furnace chamber laterally adjoining the spacecontaining said tube bank and communicating therewith at only one end,boiler setting walls, bafile means extending transversely of said tubespace and co-operating with said setting walls to divide said space intoa plurality of serially connected gas passes extending transversely ofsaid tube bank, means for burning fuel in said furnace chamber andeffecting a substantially horizontal flow of heating gaseslongitudinally from said furnace chamber and reversely through saidserially connected gas passes, an intermediate baflle dividing the firstof said serially connected gas passes into two parallel gas passes fromwhich gases unite to pass over some of the steam generating tubes, asuperheater having its tubes disposed in one of said parallel gas passeswhile some of the steam generating tubes are disposed in the other, agas flow regulator disposed adjacent the outlet of one of the parallelgas passes and adjacent one of the boiler setting walls, and meansextending through the last named wall to operate the regulator andthereby selectively control the proportioning of furnace gas flowbetween the parallel passes and thereby control superheat.

3. A steam boiler having an upper steamand water drum, a lower waterdrum, a vertically disposed convection heated bank of steam generatingtubes extending between and connected to said drums along the lengththereof, means forming a furnace chamber laterally of the spacecontaining said tube bank and communicating therewith at only one end,bafile means extending transversely of said tube space and arranged todivide said tube space into a plurality of serially connected gas passesextending transversely of said tube bank, means for effecting asubstantially horizontal flow of heating gases through said seriallyconnected gas passes, an intermediate bafile dividing the first of saidserially connected gas passes into two parallel gas passes, asuperheater having its tubes disposed in one of said parallel gaspasses, and a gas flow regulator disposed adjacent the outlet of one ofthe parallel passes and adjacent one of the boiler setting Walls, andmeans extending through the last named wall to selectively control theproportioning of the furnace gas flow between the parallel passes andthereby control superheat.

CHARLES S. SMITH.

